By the time Allyson Felix was done with her part, her third gold medal of the Olympics was all but hanging around her neck. Staking the U.S. team to more than a 2-second lead at the halfway point Saturday night, then watching Sanya Richards-Ross bring home the blowout victory, Felix added the 4x400-meter relay gold to the titles she won earlier in the 4x100 relay and 200-meter sprint.
